Analysis of Two Quantitative Ultrasound Approaches

There are two well-known ultrasonic approaches to extract sets of quantitative parameters: Lizzi–Feleppa (LF) parameters: slope, intercept, and midband; and quantitative ultrasound (QUS)–derived parameters: effective scatterer diameter (ESD) and effective acoustic concentration (EAC). In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD (R² =1.00), and from experimental data, LF midband is correlated to EAC (R² =0.76). However, LF intercept is not correlated to ESD (R² =0.25) nor EAC (R² =0.07). The unexpected correlation observed between LF slope and EAC (R² =0.94) results likely from the high correlation between ESD and EAC due to the inversion process. For a liver fat percentage estimation, an important potential medical application, the parameters presenting the better correlation are EAC (R² =0.78) and LF midband (R² =0.70).